The 103-year-old organization's resolution may help garner support for gay marriage among Maryland's black voters, who according to polls have been less inclined than whites to support same-sex marriage.

A Pew Research Center poll conducted in April showed 39 percent of African-Americans favor gay marriage, compared with 47 percent of whites. The poll showed 49 percent of blacks and 43 percent of whites are opposed.

Increased approval among black voters could help overcome a ballot challenge to the state's gay marriage law, passed this year by the General Assembly.

Same-sex weddings are to be allowed in Maryland starting in January, but opponents want to put the measure on the November ballot. Earlier this month, President Barack Obama announced his support for gay marriage.

At a meeting Saturday in Miami, the board of directors of the NAACP, which is headquartered in Baltimore, passed a resolution endorsing marriage equality.

"Civil marriage is a civil right and a matter of civil law," NAACP President and CEO Benjamin Todd Jealous said in a statement. "The NAACP's support for marriage equality is deeply rooted in the Fourteenth Amendment of the United States Constitution and equal protection of all people."

Human Rights Campaign, a national nonprofit that focuses on advancing civil rights for gay, lesbian, bisexual and transgender people, called the NAACP's vote a "landmark move."

"It's time the shameful myth that the African-American community is somehow out of lockstep with the rest of the country on marriage equality is retired — once and for all," Joe Solmonese, the group's president, said in a statement. "The facts and clear momentum toward marriage speak for themselves."

Here is the full text of the NAACP resolution:

"The NAACP Constitution affirmatively states our objective to ensure the 'political, educational, social and economic equality' of all people. Therefore, the NAACP has opposed and will continue to oppose any national, state, local policy or legislative initiative that seeks to codify discrimination or hatred into the law or to remove the Constitutional rights of LGBT citizens. We support marriage equality consistent with equal protection under the law provided under the Fourteenth Amendment of the United States Constitution. Further, we strongly affirm the religious freedoms of all people as protected by the First Amendment."